This invention relates to methods and systems for performing a medical procedure, especially procedures during which it is necessary to adjust the beating of the heart. More particularly, this invention relates to methods and systems for sensing imminent cardiac contractions during such a procedure.
The current leading cause of death in the United States is coronary artery disease in which the coronary arteries are blocked by atherosclerotic plaques or deposits of fat. The typical treatment to relieve a partially or fully blocked coronary artery is coronary artery bypass graph (CABG) surgery.
CABG surgery, also known as xe2x80x9cheart bypassxe2x80x9d surgery, generally entails using a graph to bypass the coronary obstruction. The procedure is generally lengthy, traumatic and subject to patient risks. Among the risk factors involved is the use of a cardiopulmonary bypass (CPB) circuit, also known as a xe2x80x9cheart-lung machinexe2x80x9d, to pump blood and oxygenate the blood so that the patient""s heart may be stopped during the surgery.
Conventional CABG procedures are typically conducted on a stopped heart while the patient is on a CPB circuit. A stopped heart and a CPB circuit enables a surgeon to work in a bloodless, still operative field. However, there are a number of problems associated with CABG procedures performed while on CPB including the initiation of a systemic inflammatory response due to interactions of blood elements with the artificial material surfaces of the CPB circuit and global myocardial ischemia due to cardioplegic cardiac arrest. For these reasons, avoiding the use of CPB or cardioplegic cardiac arrest may help minimize post-operative complications.
One method, as disclosed in U.S. Pat. No. 5,651,378 to inventors Matheny and Taylor and in U.S. Pat. No. 5,913,876 to inventors Taylor et al., for facilitating coronary bypass surgery on a beating heart and thereby avoid the use of CPB and cardioplegic cardiac arrest includes stimulating the vagal nerve electrically in order to temporarily stop or substantially reduce the beating of the heart. This may be followed by pacing the heart to start its beating.
Another method, as disclosed in two published PCT applications, WO 99/09971 and WO 99/09973, both to inventor Puskas, involves stopping the beating of the heart during coronary bypass surgery using electrical stimulation of the vagal nerve in combination with administration of drugs. Another method, as disclosed in U.S. Pat. No. 6,060,454 to inventor Duhaylongsod, involves stopping the beating of the heart during coronary bypass surgery via the local delivery of drugs to the heart.
Although it is desirable to stop the heart for a period of time in order to allow the surgeon to accomplish a required task without interference from heart movement, i.e. a motionless operative field, it is undesirable to have the heart stopped for too long a period of time since the body needs, among other things, a constant supply of oxygen. In fact, it is particularly important to maintain sufficient blood flow, and therefore oxygen flow, to the brain. Stopping the heart for prolonged periods of time may cause damage to the patient.
Moreover, once stopped or still, the heart may still contract occasionally. This is sometimes referred to as an xe2x80x9cescape beat.xe2x80x9d Such an xe2x80x9cescape beatxe2x80x9d may occur without any warning to the surgeon and the movement associated with the escape beat may interfere with the medical procedure being carried out.
It would be desirable therefore to provide a method for temporarily stopping or slowing the heart in order to control blood flow during a medical procedure.
It would further be desirable to provide a means for sensing an imminent cardiac contraction during the procedure.
It would further be desirable to provide a means for alerting the surgeon of an imminent contraction during the procedure.
One aspect of the present invention provides a system for performing a medical procedure. The system includes a sensor to sense a state of a cardiac tissue and an indicator to indicate the state of the cardiac tissue.
The system may also include a nerve stimulator in communication with the sensor to inhibit beating of a heart when the state indicated by the indicator is a non-contracting state. The nerve stimulator may stimulate a nerve such as a vagal nerve, a carotid sinus nerve, a fat pad. The nerve stimulator may be, for example, one or more electrodes, such as nerve stimulation electrodes, endotracheal electrodes, endoesophageal electrodes, intravascular electrodes, transcutaneous electrodes, intracutaneous electrodes, balloon-type electrodes, basket-type electrodes, umbrella-type electrodes, tape-type electrodes, suction-type electrodes, screw-type electrodes, barb-type electrodes, bipolar electrodes, monopolar electrodes, metal electrodes, wire electrodes, patch electrodes, cuff electrodes, clip electrodes, needle electrodes and probe electrodes.
The system may also include a cardiac stimulator in communication with the sensor to stimulate beating of a heart when the state indicated by the indicator is a contracting state. The cardiac stimulator may be, for example, one or more electrodes, such as cardiac stimulation electrodes, clip electrodes, needle electrodes, probe electrodes, pacing electrodes, epicardial electrodes, patch electrodes, intravascular electrodes, balloon-type electrodes, basket-type electrodes, tape-type electrodes, umbrella-type electrodes, suction-type electrodes, endotracheal electrodes, endoesophageal electrodes, transcutaneous electrodes, intracutaneous electrodes, screw-type electrodes, barb-type electrodes, bipolar electrodes, monopolar electrodes, metal electrodes, wire electrodes and cuff electrodes.
The sensor may be an electrical sensor, a chemical sensor, an electromagnetic interference sensor, an electrochemical sensor, a pressure sensor, a sound wave sensor, a magnetic sensor, an ultraviolet sensor, a visible light sensor, an infrared sensor, a radiation sensor, a flow sensor, a temperature sensor, a gas sensor, an optical sensor, a pH sensor, a potentiometric sensor, a fluorescence sensor, a depolarization sensor and a biosensor. The sensor may also comprise one or more electrodes, such as cardiac stimulation electrodes, clip electrodes, needle electrodes, probe electrodes, pacing electrodes, epicardial electrodes, patch electrodes, intravascular electrodes, balloon-type electrodes, basket-type electrodes, tape-type electrodes, umbrella-type electrodes, suction-type electrodes, endotracheal electrodes, endoesophageal electrodes, transcutaneous electrodes, intracutaneous electrodes, screw-type electrodes, barb-type electrodes, bipolar electrodes, monopolar electrodes, metal electrodes, wire electrodes and cuff electrodes. The sensor and the cardiac stimulator may be the same.
The system may also include drug delivery means such as a spray, a cream, an ointment, a medicament, a pill, a patch, a catheter, a cannula, a needle and syringe, a pump, and an iontophoretic drug delivery device to deliver at least one drug during the procedure. The drug may be a beta-blocker, a cholinergic agent, a cholinesterase inhibitor, a calcium channel blocker, a sodium channel blocker, a potassium channel agent, adenosine, an adenosine receptor agonist, an adenosine deaminase inhibitor, dipyridamole, a monoamine oxidase inhibitor, digoxin, digitalis, lignocaine, a bradykinin agent, a serotoninergic agonist, an antiarrythmic agent, a cardiac glycoside, a local anesthetic, atropine, a calcium solution, an agent that promotes heart rate, an agent that promotes heart contractions, dopamine, a catecholamine, an inotrope glucagon, a hormone, forskolin, epinephrine, norepinephrine, thyroid hormone, a phosphodiesterase inhibitor, prostacyclin, prostaglandin and a methylxanthine. The drug may be naturally occurring or chemically synthesized.
The system may also include a breathing regulator, which may control a respirator. The breathing regulator may stimulate a phrenic nerve. The breathing regulator may be, for example, one or more electrodes such as nerve stimulation electrodes, endotracheal electrodes, endoesophageal electrodes, intravascular electrodes, transcutaneous electrodes, intracutaneous electrodes, balloon-type electrodes, basket-type electrodes, umbrella-type electrodes, suction-type electrodes, screw-type electrodes, tape-type electrodes, barb-type electrodes, bipolar electrodes, monopolar electrodes, metal electrodes, wire electrodes, patch electrodes, cuff electrodes, clip electrodes, needle electrodes and probe electrodes.
The medical procedure may be a surgical procedure, a non-surgical procedure, a fluoroscopic procedure, a cardiac procedure, a vascular procedure, a neurosurgical procedure, an electrophysiological procedure, a diagnostic procedure, a therapeutic procedure, an ablation procedure, an endovascular sprocedure, a liver procedure, a spleen procedure, a pulmonary procedure, an aneurysm repair, an imaging procedure, a CAT scan procedure, a MRI procedure, a pharmacological therapy, a drug delivery procedure, a biological delivery procedure, a genetic therapy, a cellular therapy, a cancer therapy, a radiation therapy, a transplantation procedure, a coronary angioplasty procedure, a stent delivery procedure, an atherectomy procedure, a procedure that requires precise control of cardiac motion, a procedure that requires precise control of bleeding, a non-invasive procedure, a minimally invasive procedure, an invasive procedure, a port-access procedure, an endoscopic procedure, a sternotomy procedure, a thoracotomy procedure and a robotic procedure.
Another aspect of the present invention provides a method for performing a medical procedure. Beating of a heart is inhibited. The medical procedure is performed and a state of cardiac tissue is sensed while beating of the heart is inhibited. The beating of the heart may be inhibited automatically when the state of cardiac tissue is a non-contracting state. A nerve may also be stimulated to inhibit beating of the heart when the state of cardiac tissue is a non-contracting state. Stimulation of the nerve may be stopped when the state of cardiac contraction is a contracting state. Beating of the heart may be allowed to occur when the state of cardiac tissue is a contracting state. Beating of the heart may also be stimulated automatically when the state of cardiac tissue is a contracting state. At least one drug may be delivered during the medical procedure. Breathing may be stopped when the state of cardiac tissue is a non-contracting state.
Another aspect of the present invention provides a device for performing a medical procedure. The device includes a processor, a sensor to sense a state of cardiac tissue and at least one nerve stimulation electrode. The processor receives a signal from the sensor and adjusts output from the nerve stimulation electrode in response to the signal. The sensor may be an electrical sensor, a chemical sensor, an electromagnetic interference sensor, an electrochemical sensor, a pressure sensor, a sound wave sensor, a magnetic sensor, an ultraviolet sensor, a visible light sensor, an infrared sensor, a radiation sensor, a flow sensor, a temperature sensor, a gas sensor, an optical sensor, a pH sensor, a potentiometric sensor, a fluorescence sensor, a depolarization sensor and a biosensor. The nerve stimulation electrode may be, for example, one or more electrodes such as endotracheal electrodes, endoesophageal electrodes, intravascular electrodes, transcutaneous electrodes, intracutaneous electrodes, balloon-type electrodes, basket-type electrodes, umbrella-type electrodes, tape-type electrodes, suction-type electrodes, screw-type electrodes, barb-type electrodes, bipolar electrodes, monopolar electrodes, metal electrodes, wire electrodes, patch electrodes, cuff electrodes, clip electrodes, needle electrodes and probe electrodes.
The device may also include at least one cardiac stimulation electrode to stimulate beating of the heart. The processor receives a signal from the sensor and adjusts output from the cardiac stimulation electrode in response to the signal. The cardiac stimulation electrode may be, for example, one or more electrodes such as clip electrodes, needle electrodes, probe electrodes, pacing electrodes, epicardial electrodes, patch electrodes, intravascular electrodes, balloon-type electrodes, basket-type electrodes, tape-type electrodes, umbrella-type electrodes, suction-type electrodes, endotracheal electrodes, endoesophageal electrodes, transcutaneous electrodes, intracutaneous electrodes, screw-type electrodes, barb-type electrodes, bipolar electrodes, monopolar electrodes, metal electrodes, wire electrodes and cuff electrodes. The cardiac stimulation electrode and the sensor may be the same.
The device may also include at least one breathing regulation electrode for controlling breathing. The processor adjusts the output from the breathing regulation electrode in response to the signal. The breathing electrode may be, for example, one or more electrodes, such as nerve stimulation electrodes, endotracheal electrodes, endoesophageal electrodes, intravascular electrodes, transcutaneous electrodes, intracutaneous electrodes, balloon-type electrodes, basket-type electrodes, umbrella-type electrodes, suction-type electrodes, screw-type electrodes, tape-type electrodes, barb-type electrodes, bipolar electrodes, monopolar electrodes, metal electrodes, wire electrodes, patch electrodes, cuff electrodes, clip electrodes, needle electrodes and probe electrodes.
The device may also include a drug pump for delivering at least one drug. The processor adjusts the output of the drug.